抄録
A superconducting “chopper”-amplifier with no movable parts and of d. c. voltage sensitivity better than 10-10 volts when used free from the effect of magnetic field, better than 10-9 volts when used in a magnetic field up to 7 K. Oe., is described.
Compactness of cryostat equipment and stability of apparatus were the chief requirements in designing. Though the use in magnetic field and the setting of temperature as desired are not without difficulty, the instrument proved useful for the study of thermoelectric and galvano-magnetic effects in metals at low temperatures.
